Duration

[eta150]

It's headed to nats, and I'm not sure if it was a total fluke, but I know for a fact that that helicopter has flown well over 3:00 in practice without any help.

[mrsteven]

I would believe a little over 3:00 but any more than that I'd have to see to believe.
That's a great time! I look forward to seeing it at nationals fly

[jarrred_1415]

I would believe a little over 3:00 but any more than that I'd have to see to believe.
That's a great time! I look forward to seeing it at nationals fly

i think a 3:30 plus is completely pausible. having built a heli that routenily gets over 3 minutes i can see where the improvements would be made and would not doubt it

[mrsteven]

ok, well I am really excited to see it, and hopefully have some of the people will share some of their ideas...

[sj]

removed by me cuz i posted in the wrong place

[sj]

What kinds of qualities are common to helicopters that are flying over 2:30?

Do they have low angle of attacks?
Small angle between spars?
Curved Ribs?

Also what is the best way to make curved ribs?

How high of a ceiling are these helicopters that are getting these kinds of times being flown on?

We are getting 2:20 - 2:30 on a 20 -25 ft ceiling and are struggling to raise our time. We are not using curved ribs and are just at the mass limit, using the max amount of rubber, matched rubber to the rotors, etc. I just get this feeling there is one or two key ideas we are missing or over looking.

Any help would be much appreciated! Thanks!

[mrsteven]

definitely use curved ribs, airfoils are extremely more efficent. if you soak the balsa in hot water for a few minutes than stroke the balsa across a light bulb (60 watt etc) until its at desired curve. Let it dry, I know that works but if you have the money and the time I'd order them from someone with a lazer cutter

[sj]

Sadly we lack time but we will certainly be experimenting with curved ribs. We are hoping to pull our selves up to 2:45 on our 20 foot ceiling by nationals.

[mrsteven]

Sadly we lack time but we will certainly be experimenting with curved ribs. We are hoping to pull our selves up to 2:45 on our 20 foot ceiling by nationals.

welll good luck to you!

[illusionist]

Here is a video I found illustrating the "light bulb" method of curving balsa: http://www.youtube.com/watch?v=QRHOBNWByDA